Measurements of Oxidative Stress

Since oxidative stress is the result of an abnormal balance between pro-oxidative and anti-oxidative processes involving many enzymes and signaling molecules, whole 

75 Predicting Drug-Induced Hepatotoxicity In Vitro, In Silica and In Vivo Approaches 

Critical Review Is There Sufficient Clinical, Pre-Clinical and In Vitro Data to Substantiate the Link Between Oxidative Stress and Idiosyncratic Liver Injury  

The best evidences are studies from preclinical animal models [86, 87, 105], or knockout animals lacking appropriate anti-oxidative pathways [106]. For example, Balb/c mice administered a variety of anti-oxidants in their chow were protected from acetaminophen hepatotoxicity [107]. Rats fed with the anti-oxidant melatonin were protected from cholesterol mediated oxidative liver damage [108]. The best clinical evidence that oxidative stress is a key player in a variety of liver injury diseases is the beneficial application of silymarin in these disease indications [109]. Silymarin is a polyphenolic plant fiavonoid (a mixture of flavonoid isomers such as silibinin, isosilibinin, silidianin and silichristin) derived from Silymarin maria-num that has antioxidative, antilipid peroxidative, antifibrotic and anti-inflammatory effects [109, 110]. 

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Although the cellular concentrations of lycopene or its oxidation products may be too low to have a general antioxidant or pro-oxidant effect on cells, there is sufficient evidence of its in vivo effect on the classical measures of oxidative stress to indicate that its participation in the redox state... 

F2-isoprostanes in biological fluids and tissues as a measure of oxidant stress. Methods Enzymol. 1999 300 3. 29. 

Pryor, W.A. and Godber, S.S. (1991) Noninvasive measures of oxidative stress status in humans. Free Radical Biol. Med. 10 177-184. 

As illustrated in Fig. 4, oxidation of fatty acids cannot occur without the formation of peroxides therefore, concentrations of lipid peroxides are a measure of oxidative stress. Most tests for lipid peroxides use simple spec-trophotometric end points and are applicable for clinical laboratory use. They do not measure specific products but reflect overall oxidation of fatty acids. HPLC can be used to specifically measure individual peroxides (S2). 

R.A. (2002) Dietary Hydroxy Fatty Acids Are Absorbed in Humans Implications for the Measurement of Oxidative Stress In Vivo, Free Radio. Biol. Med. 32,162-168. 

Wilson, R., K. Lyall, L. Smyth, C.E. Femie, and R.A. Riemersma. 2002. Dietary hydroxy fatty acids are absorbed in humans Implications for the measurement of oxidative stress in vivo. Free Radical Biolopv Medicine 32 162-8. 

Winnik WM, Kitchin KT. Measurement of oxidative stress parameters using liquid chromatography—tandem mass spectroscopy (LC-MS/MS). Toxicol Appl Pharmacol 2008 233 100-106. 

Antioxidants counteract oxidative stress and thereby lower the risk of the chronic and degenerative diseases (Figure 11.2) [4,10]. Human sahva is rich in antioxidants, such as uric acid, albumin, vitamin C and enzymes, which can be used as biomarkers in the measurement of oxidative stress in the oral cavity [13]. Since oxidative stress in the oral cavity can also be linked to certain systemic diseases [12], measiu-ement of these biomarkers in saliva may provide an accurate indicator of oxidative stress in the body [13]. 

ROBERTS L J, MORROW J D (2000) Measurement of F2-isoprostanes as an index of oxidative stress in vivo, Free Radical Biology and Medicine, 28, 505-13. 

Figure 4.7 Changes in intraceiiuiar calcium in cultured rat ventricular myocytes exposed to oxidant stress. Calcium was measured using the fluorescent probe Fura>2. The ratio of the Fura-2 fluorescence measured at 340 and 380 nm excitation is shown and this is proportional to the intracellular calcium concentration. The fast-speed traces shown (note the 3.5 s time-scale) were recorded after various durations of oxidant stress. Myocytes under control conditions (before t = 0) show spontaneous calcium transients. These transients decreased in frequency with oxidant stress until cells failed to show spontaneous activity but continued to maintain a low intracellular calcium.

Oxidative damage to membrane polyunsaturated fatty acids leads to the formation of numerous lipid peroxidation products, some of which can be measured as index of oxidative stress, including hydrocarbons, aldehydes, alcohols, ketones, and short carboxylic acids. 

In vivo studies were also conducted by several researchers. Anraku et al. (2009) examined the antioxidant effects of water-soluble chitosan in normal subjects by measuring the reduction of indices of oxidative stress. Treatment with chitosan for 4weeks produced a significant decrease in levels of plasma glucose and the atherogenic index, and led to an increase in high-density lipoprotein cholesterol (HDL-C). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity. Further, Anraku et al. (2011) proved the antioxidant effects of high MW chitosan in normal volunteers, and the obtained results were consistent with previous results observed by Anraku et al. (2009). 

The measurements of glutathione reflect the total capacity of decontamination of oxidative stress within the cornea. The glutathione system gives the outer... 

Halliwell B, Long L, Lee T, Lim S, Kelly R. 2004. Establishing biomarkers of oxidative stress The measurement of hydrogen peroxide in human urine. Curr Med Chem 11 1085-10392. 

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